Gas purifiers are necessary because they assist in providing a clean gas stream, that may guarantee the grade of the gas chromatographic analysis and the reliability of the outcomes. Further, such gas purifiers minimize detector noise and prolong the life of the column. Gas purifiers are like plans to safeguard the instrumentation along with other analytical columns from different types of contaminants. Still, the gas purifiers will never be in a position to convert low purity gases into high purity gases. Due to this important factor, it is necessary to select the right grade of gases with different purity levels for proper use in gas chromatographic applications.
Collection of Right Gas Purifier to Suit Your Applications
Numerous kinds of gas purifiers can be purchased in the market. While some gas purifiers remove just one specific contaminant, other types remove multiple contaminants simultaneously from the gas stream. You need to think about several factors during the selection process of gas purifiers, taking into consideration your unique applications. These factors will include the potential contaminants present in the gas stream, the limitations on flow and pressure, levels of gas purity required, desired convenience in replacement of spent gas traps, and space availability.
Common Traps Found in Gas Purifiers
Oxygen, hydrocarbon, skin tightening and, and moisture traps will be the most common purifiers found in most the gas chromatography (GC) applications. Oxygen traps are normally filled with metal catalysts. Oxygen is recognized as the most detrimental contaminating gas in every analytical columns. Oxygen is capable of producing irreversible oxidation damage, especially to polar stationary phases. Hydrocarbon traps are typically packed with activated charcoal, that may absorb organic compounds that are larger than methane. Still, the molecular weight and size of the organic contaminants will have a definite influence on the capacity of the hydrocarbon trap to an excellent extent but it will also think about trap efficiency somewhat.
Activated charcoal possesses an increased capacity to trap larger hydrocarbons which are greater than C4, in comparison to smaller hydrocarbons, which are lesser than C4. Moisture traps are often packed with unique molecular sieves. When put through extensive heating, the crystalline structures are forced to reduce their hydration or water content. This opens a cavity which gets filled readily with any compound that can fit the cavity. Water fits perfectly into this cavity but this trap will also be in a position to remove gases like carbon dioxide, sulfur dioxide, hydrogen chloride, and chlorine or other gases which have effective diameters lesser than water.
Procedure for Contaminants Affecting Gas Stream
If you wish to understand how the contaminants affect the gas stream, you will need to follow the path that the carrier gas takes to get into the gas chromatograph. This path is applicable for detector fuel gases also. The gases begin from a gas tank or perhaps a special gas generator. The gas travels through long lengths of tubes, pressure gauges, valves, and various other fittings. Every one of these areas is a potential culprit to introduce contaminants in to the gas stream. This leads not only in degrading the outcomes of chromatography but also shortens the life of the column of CG.
Major contaminants like oxygen, hydrocarbons, and moisture can handle wreaking havoc with the columns and detectors of CG. The packed and capillary columns can get degraded easily if they face oxygen or moisture, especially at high temperatures. These contaminants may also compromise detector performance. Because the detectors actually ‘see’ these contaminants, the effect is baseline noises, spikes, and drifts.
headspace sampler is advisable to install gas purifiers in a vertical position as wall mounted types to avoid channeling. Channeling occurs when you install the gas purifier in a horizontal position. Gas purifiers are available as compact panels having multiple purifiers or single panel which has multi-absorbent capabilities.